A mobile communication system has evolved to provide various high-speed large-capacity services to mobile stations (MSs). Examples of a mobile communication system include a high speed downlink packet access (HSDPA) mobile communication system, a high speed uplink packet access (HSUPA) mobile communication system, a long-term evolution (LTE) mobile communication system, an LTE-advanced (LTE-A) mobile communication system, a high rate packet data (HRPD) mobile communication system proposed by the 3rd generation partnership project 2 (3GPP2), and an institute of electrical and electronics engineers (IEEE) 802.16m mobile communication system.
Recently, the number of MSs which support a plurality of radio interfaces for a communication such as in a 3rd generation (3G) system, a Wi-Fi system, and the like, has increased, so significance for an MPTCP in which a plurality of network links may be recognized and used in a transport layer has increased.
The MPTCP has been proposed for increasing transmission control protocol (TCP) throughput and reliability based on diversity by allowing usage of a plurality of paths per TCP session, compared to a single path TCP of the related art.
A process of transmitting/receiving a data packet based on an MPTCP in a wireless communication system of the related art will be described with reference to FIG. 1.
FIGS. 1A and 1B schematically illustrate a process of transmitting/receiving a data packet based on an MPTCP in a wireless communication system of the related art.
Referring to FIG. 1A, a transmitting apparatus 100 may transmit data packets to be transmitted to a receiving apparatus 120 through a plurality of paths. The transmitting apparatus 100 may transmit a data packet #9, a data packet #8, a data packet #6, and a data packet #4 among the data packet #9, the data packet #8, a data packet #7, the data packet #6, a data packet #5, and the data packet #4 as the data packets to be transmitted to the receiving apparatus 120 through a path #1 110 among two paths, and transmit the data packet #1 and the data packet #5 through a path #2 130 to the receiving apparatus 120 through a path #2 130 among the two paths.
Referring to FIG. 1B, the transmitting apparatus 100 may duplicately transmit the same data packet through the two paths in order to prevent loss of the data packets to be transmitted. That is, the transmitting apparatus 100 may transmit the data packet #7, the data packet #5, the data packet #9, the data packet #8, the data packet #6, and the data packet #4 to the receiving apparatus 120 through the path #1 110, and may transmit the data packet #7 and the data packet #5 as a part of data packets which have been transmitted through the path #1 110 to the receiving apparatus 120 through the path #2 130.
In this case, even though the data packets which have been transmitted through the path #2 130 are lost, the receiving apparatus 120 may receive all data packets through the path #1 110, so the receiving apparatus 120 may successfully perform a decoding operation.
In the wireless communication system supporting the MPTCP, TCP throughput may decrease due to data packet loss which may occur in each path. For this reason, there are out-of-ordered data packets if data packet loss occurs, so a TCP window size decreases.
In the wireless communication system supporting the MPTCP, qualities of paths are different one another, so a transmission delay for a data packet may occur. If the transmission delay for the data packet occurs, a decoding delay for the data packet also occurs, so data throughput decreases.
Accordingly, in the wireless communication system supporting the MPTCP, there is a need for a method of effectively transmitting/receiving a data packet by considering a characteristic of each path and a problem which may occur in each path.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.